Modulation of Methoxyfenozide Release from Lignin Nanoparticles Made of Lignin Grafted with PCL by ROP and Acylation Grafting Methods

An efficient and sustainable agriculture calls for the development of novel agrochemical delivery systems able to release agrochemicals in a controlled manner. This study investigated the controlled release of the insecticide methoxyfenozide (MFZ) from lignin (LN) nanoparticles (LNPs). LN-grafted poly(ε-caprolactone) (LN-g-PCL) polymers were synthesized using two grafting methods, ring-opening polymerization (ROP)(LN-g-PCLp) and acylation reaction (LN-g-PCLa), creating polymers capable of self-assembling into nanoparticles of different properties, without surfactants. The LN-g-PCLp polymers exhibited a degree of polymerization (DP) from 22 to 101, demonstrating enhanced thermal stability after LN incorporation. LNPs loaded with MFZ exhibited a spherical core-shell structure with a hydrophilic LN outer layer and hydrophobic PCL core, with sizes affected by grafting methods and DP. LNPs controlled MFZ release, displaying variation in release profiles depending on the grafting methodology used, LN-g-PCLp DP, and temperature variations (23 to 30 °C). LNPs formulated with LN-g-PCLa showed a cumulative release of MFZ of 36.78 ± 1.23% over 196 h. Comparatively, increasing the DP of the LN-g-PCLp polymers, a reduction of the LNPs release rate from 92.39 ± 1.46% to 70.59 ± 2.40% was achieved within the same time frame. These findings contribute to identifying ways to modulate the controlled release of agrochemicals by incorporating them in renewable-based LNPs.

α-Aminobisphosphonate Copolymers Based on Poly(ε-caprolactone)s and Poly(ethylene glycol): A New Opportunity for Actinide Complexation

Original α-aminobisphosphonate-based copolymers were synthesized and successfully used for actinide complexation. For this purpose, poly(α-chloro-ε-caprolactone-co-ε-caprolactone)-b-poly(ethylene glycol)-b-poly(α-chloro-ε-caprolactone-co-ε-caprolactone) copolymers were first prepared by ring-opening copolymerization of ε-caprolactone (εCL) and α-chloro-ε-caprolactone using poly(ethylene glycol) (PEG) as a macro-initiator and tin(II) octanoate as a catalyst. The chloride functions were then converted to azide moieties by chemical modification, and finally α-aminobisphosphonate alkyne ligand (TzBP) was grafted using click chemistry, to afford well-defined poly(αTzBPεCL-co-εCL)-b-PEG-b-poly(αTzBPεCL-co-εCL) copolymers. Three copolymers, showing different α-aminobisphosphonate group ratios, were prepared (7, 18, and 38%), namely, CP8, CP9, and CP10, respectively. They were characterized by 1H and 31P NMR and size exclusion chromatography. Sorption properties of these copolymers were evaluated by isothermal titration calorimetry (ITC) with neodymium [Nd(III)] and cerium [Ce(III)] cations, used as surrogates of actinides, especially uranium and plutonium, respectively. ITC enabled the determination of the full thermodynamic profile and the calculation of the complete set of thermodynamic parameter (ΔH, TΔS, and ΔG), with the Ka constant and the n stoichiometry. The results showed that the number of cations sorbed by the functional copolymers logically increased with the number of bisphosphonate functions borne by the macromolecular chain, independently of the complexed cation. Additionally, CP9 and CP10 copolymers showed higher sorption capacities [21.4 and 34.0 mg·g-1 for Nd(III) and 9.6 and 14.3 mg·g-1 for Ce(III), respectively] than most of the systems previously described in the literature. CP9 also showed a highest binding constant (7000 M-1). These copolymers, based on non-toxic and biocompatible poly(ε-caprolactone) and PEG, are of great interest for external body decontamination of actinides as they combine high number of complexing groups, thus leading to great decontamination efficiency, and limited diffusion through the skin due to their high-molecular weight, thus avoiding additional possible internal contamination.

Innovative Design of Targeted Nanoparticles: Polymer-Drug Conjugates for Enhanced Cancer Therapy

Polymer-drug conjugates (PDCs) have shown great promise in enhancing the efficacy and safety of cancer therapy. These conjugates combine the advantageous properties of both polymers and drugs, leading to improved pharmacokinetics, controlled drug release, and targeted delivery to tumor tissues. This review provides a comprehensive overview of recent developments in PDCs for cancer therapy. First, various types of polymers used in these conjugates are discussed, including synthetic polymers, such as poly(↋-caprolactone) (PCL), D-α-tocopheryl polyethylene glycol (TPGS), and polyethylene glycol (PEG), as well as natural polymers such as hyaluronic acid (HA). The choice of polymer is crucial to achieving desired properties, such as stability, biocompatibility, and controlled drug release. Subsequently, the strategies for conjugating drugs to polymers are explored, including covalent bonding, which enables a stable linkage between the polymer and the drug, ensuring controlled release and minimizing premature drug release. The use of polymers can extend the circulation time of the drug, facilitating enhanced accumulation within tumor tissues through the enhanced permeability and retention (EPR) effect. This, in turn, results in improved drug efficacy and reduced systemic toxicity. Moreover, the importance of tumor-targeting ligands in PDCs is highlighted. Various ligands, such as antibodies, peptides, aptamers, folic acid, herceptin, and HA, can be incorporated into conjugates to selectively deliver the drug to tumor cells, reducing off-target effects and improving therapeutic outcomes. In conclusion, PDCs have emerged as a versatile and effective approach to cancer therapy. Their ability to combine the advantages of polymers and drugs offers enhanced drug delivery, controlled release, and targeted treatment, thereby improving the overall efficacy and safety of cancer therapies. Further research and development in this field has great potential to advance personalized cancer treatment options.

Amphiphilic Graft Copolymers for Time-Delayed Release of Hydrophobic Fragrances

When a controlled or retarded release of perfumes is required such as in cosmetics or cleaning products, polymers can be applied as encapsulation agents. With regard to such applications, we investigated two amphiphilic graft copolymers featuring a polydehydroalanine (PDha) backbone and different hydrophobic side chains. Hereby, grafting of aliphatic octyl side chains (PDha-g-EOct) enabled the adsorption of the aliphatic fragrance tetrahydrolinalool with moderate loads, whereas benzyl side chains (PDha-g-BGE) allowed taking up aromatic fragrances, for example, amylsalicylate-n with exceptionally high loads of up to 8 g g^-1. The side-chain density was studied as well but had no significant influence on the loading. In addition, the characterization and quantification of the load by NMR and thermogravimetric analysis were compared, and it was also possible to load the aromatic model fragrance into the graft copolymer with aliphatic side chains. After 3 months, the load had decreased by 40-50% and, hence, such systems are of interest for a long-term release of perfumes over months. Although this study is a proof-of-concept, we foresee that such polyampholytic graft copolymers can be tailored for the adsorption of a variety of hydrophobic perfumes simply by altering polarity and chemistry of the side chain.

Poly(ε-caprolactone)-Based Graft Copolymers: Synthesis Methods and Applications in the Biomedical Field: A Review

Synthetic biopolymers are attractive alternatives to biobased polymers, especially because they rarely induce an immune response in a living organism. Poly ε-caprolactone (PCL) is a well-known synthetic aliphatic polyester universally used for many applications, including biomedical and environmental ones. Unlike poly lactic acid (PLA), PCL has no chiral atoms, and it is impossible to play with the stereochemistry to modify its properties. To expand the range of applications for PCL, researchers have investigated the possibility of grafting polymer chains onto the PCL backbone. As the PCL backbone is not functionalized, it must be first functionalized in order to be able to graft reactive groups onto the PCL chain. These reactive groups will then allow the grafting of new reagents and especially new polymer chains. Grafting of polymer chains is mainly carried out by "grafting from" or "grafting onto" methods. In this review we describe the main structures of the graft copolymers produced, their different synthesis methods, and their main characteristics and applications, mainly in the biomedical field.

Lipase-triggered drug release from BCL2 inhibitor ABT-199-loaded nanoparticles to elevate anti-leukemic activity through enhanced drug targeting on the mitochondrial membrane

Selective BCL2 inhibitor ABT-199 has been approved to treat hematological malignancies including acute myeloid leukemia (AML). However, acquired drug resistance and severe side effects occur after extended treatment limiting the clinical usage of ABT-199. Here, we successfully encapsulated pure ABT-199 in amphiphilic mPEG-b-PTMC₁₆₉ block copolymer, forming mPEG-b-PTMC₁₆₉@ABT-199 nanoparticles (abbreviated as PEG-ABT-199), which presented better aqueous dispersion and higher efficiency of loading and encapsulation than pure ABT-199. We then compared the anti-leukemic ability of pure ABT-199 and PEG-ABT-199 in vitro and in vivo. PEG-ABT-199 had a lower IC50 value compared with pure ABT-199 in MV4-11 and MOLM-13 cell lines. In addition, PEG-ABT-199 significantly induced apoptosis and decreased colony number than pure ABT-199. Most importantly, PEG-ABT-199 markedly reduced leukemic burden, inhibited the infiltration of leukemic blasts in the spleen, and extended the overall survival (OS) in MLL-AF9-transduced murine AML compared with free ABT-199. Meanwhile, the blank PEG169 NP was non-toxic to normal hematopoiesis in vitro and in vivo, suggesting that PEG169 NP is a safe carrier. Mechanistically, PEG-ABT-199 enhanced mitochondria-targeted delivery of ABT-199 to trigger the collapse of mitochondrial membrane potential (MMP), the release of cytochrome c (cyt-c), and mitochondria-based apoptosis. In conclusion, our results suggest that PEG-ABT-199 has more vital anti-leukemic ability than pure ABT-199. PEG-ABT-199 has potential application in clinical trials to alleviate side effects and improve anti-leukemia ability. STATEMENT OF SIGNIFICANCE: ATB-199, an orally selective inhibitor for BCL2 protein, presents marked activity in relapsed or refractory AML, T-ALL, and CLL patients. However, ABT-199 resistance severely limits the further clinical usage because of off-target effects, non-specific toxicities, and low delivery of drugs. To reduce the side-effects and improve the solubility and bioavailability, ABT-199 was encapsulated into the amphiphilic mPEG-b-PTMC block copolymer by co-assembly method to obtain mPEG-b-PTMC@ABT-199 nanoparticles (PEG-ABT-199). PEG-ABT-199 has several advantages compared with pure ABT-199. 1.PEG-ABT-199 presents better aqueous dispersion and higher efficiencies of loading and encapsulation than pure ABT-199. 2. PEG-ABT-199 substantially enhances the anti-leukemic ability in vitro and in vivo compared with pure ABT-199. 3. PEG-ABT-199 has little effects on normal cells. 4. PEG-ABT-199 can reduce treatment cost.

Recent advances in the self-assembly of sparsely grafted amphiphilic copolymers in aqueous solution

This review describes the self-assembly of sparsely grafted amphiphilic copolymers and highlights the effects of structural factors and solvents on their self-assembly behaviour.

Polymer based nanoparticles for biomedical applications by microfluidic techniques: from design to biological evaluation

The development of microfluidic technologies represents a new strategy to produce and test drug delivery systems.

Pluronic-based nanovehicles: Recent advances in anticancer therapeutic applications

Pluronics are a class of amphiphilic tri-block copolymers with wide pharmaceutical applicability. In the past decades, the ability to form biocompatible nanosized micelles was exploited to formulate stable drug nanovehicles with potential use in antitumor therapy. Due to the great potential for tuning physical and structural properties of Pluronic unimers, a panoply of drug or polynucleotide-loaded micelles was prepared and tested for their antitumoral activity. The attractive inherent antitumor properties of Pluronic polymers in combination with cell targeting and stimuli-responsive ligands greatly improved antitumoral therapeutic effects of tested drugs. In spite of that, the extraordinary complexity of biological challenges in the delivery of micellar drug payload makes their therapeutic potential still not exploited to the fullest. In this review paper we attempt to present the latest developments in the field of Pluronic based nanovehicles and their application in anticancer therapy with an overview of the chemistry involved in the preparation of these nanovehicles.

Development of red-light cleavable PEG-PLA nanoparticles as delivery systems for cancer therapy

The development of targeted delivery systems can improve the selectivity of cancer drugs. Additionally, a system that promotes the controlled delivery of the drug triggered by an external stimulus in the exact target tissue is highly desirable. Regarding the light stimulus, the NIR window (650-950 nm) is the most suitable due to its higher capacity of penetration in human tissues and less harmful effects on normal cells. In this work, new red-light-responsive nanoparticles for doxorubicin delivery were developed. The nanoparticles were based on cleavable di-block copolymers of poly(ethylene glycol) (PEG) and poly(lactic acid) (PLA) linked by a red-light sensitive segment (1,2-bis(2-hydroxyethylthio)ethylene, BHETE). The PEG-BHETE-PLA copolymers were synthesized under mild conditions and exhibited a narrow polydispersity. The nanoparticles presented a size between 53 and 133 nm, with a doxorubicin loading capacity between 1.2 and 4.4 wt%. Release study of the encapsulated doxorubicin confirms the light-triggered nanoparticle disassembly process. In vitro cytotoxicity tests in MCF7 cell line, for the light-triggered nanoparticles, showed a decrease in cancer cells' viability higher than 25% compared to non-irradiated cells. Due to the promising results obtained with the light-sensitive PEG-BHETE-PLA nanoparticles, these materials have great potential to be used in drug delivery systems for cancer therapy.

Graft copolymers with tunable amphiphilicity tailored for efficient dual drug delivery via encapsulation and pH-sensitive drug conjugation

Amphiphilic poly(ε-caprolactone)-graft-(poly-N-(2-hydroxypropyl) methacrylamide) copolymers with tunable solution properties form stable micelles with high drug payload via simultaneous encapsulation and pH-sensitive covalent conjugation.

Reversibly core-crosslinked PEG-P(HPMA) micelles: Platinum coordination chemistry for competitive-ligand-regulated drug delivery

HYPOTHESIS

The presence of pendant thioether groups on poly(ethylene glycol)-poly(N(2-hydroxypropyl) methacrylamide) (PEG-P(HPMA)) block copolymers allows for platinum-mediated coordinative micellar core-crosslinking, resulting in enhanced micellar stability and stimulus-responsive drug delivery.

EXPERIMENTS

A new PEG-P(HPMA) based block copolymer with pendant 4-(methylthio)benzoyl (MTB) groups along the P(HPMA) block was synthesized by free radical polymerization of a novel HPMA-MTB monomer using a PEG based macro-initiator. As crosslinker the metal-organic linker [ethylenediamineplatinum(II)]²⁺ was used, herein called Lx, which is a coordinative linker molecule that has been used for the conjugation of drug molecules to a number of synthetic or natural carrier systems such as hyperbranched polymers and antibodies.

FINDINGS

The introduction of Lx in the micellar core results in a smaller size, a lower critical micelle concentration and a better retention of the hydrophobic drug curcumin thanks to coordination bonds between the central platinum atom of Lx and thioether groups on different polymer chains. The drug release from Lx crosslinked micelles is significantly accelerated under conditions mimicking the intracellular environment due to competitive coordination and subsequent micellar de-crosslinking. Because of their straightforward preparation and favorable drug release characteristics, core-crosslinked Lx PEG-P(HPMA) micelles hold promise as a versatile nanomedicine platform.

Light- and pH-dually responsive dendrimer-star copolymer containing spiropyran groups: synthesis, self-assembly and controlled drug release

Dendrimer-star copolymer containing spiropyran groups could self-assemble into micelles and presented light- and pH-dually responsive properties.

PEG-PCL-based nanomedicines: A biodegradable drug delivery system and its application

The lack of efficient therapeutic options for many severe disorders including cancer spurs demand for improved drug delivery technologies. Nanoscale drug delivery systems based on poly(ethylene glycol)-poly(ε-caprolactone) copolymers (PEG-PCL) represent a strategy to implement therapies with enhanced drug accumulation at the site of action and decreased off-target effects. In this review, we discuss state-of-the-art nanomedicines based on PEG-PCL that have been investigated in a preclinical setting. We summarize the various synthesis routes and different preparation methods used for the production of PEG-PCL nanoparticles. Additionally, we review physico-chemical properties including biodegradability, biocompatibility, and drug loading. Finally, we highlight recent therapeutic applications investigated in vitro and in vivo using advanced systems such as triggered release, multi-component therapies, theranostics, or gene delivery systems.

d-Fructose Modification Enhanced Internalization of Mixed Micelles in Breast Cancer Cells via GLUT5 Transporters

d-Fructose modified poly(ε-caprolactone)-polyethylene glycol (PCL-PEG-Fru) diblock amphiphile is synthesized via Cu(I)-catalyzed click chemistry, which self-assembles with D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) into PCL-PEG-Fru/TPGS mixed micelles (PPF MM). It has been proven that glucose transporter (GLUT)5 is overexpressed in MCF-7 cells other than L929 cells. In this study, PPF MM exhibit a significantly higher uptake efficiency than fructose-free PCL-PEG-N₃ /TPGS mixed micelles in both 2D MCF-7 cells and 3D tumor spheroids. Also, the presence of free d-fructose competitively inhibits the internalization of PPF MM in MCF-7 cells other than L929 cells. PPF MM show selective tumor accumulation in MCF-7 breast tumor bearing mice xenografts. Taken together, PPF MM represent a promising nanoscale carrier system to achieve GLUT5-mediated cell specific delivery in cancer therapy.

Preparation of avermectin microcapsules with anti-photodegradation and slow-release by the assembly of lignin derivatives

A facile, environmentally friendly, and low-cost strategy for affording stability and the slow-release of avermectin based on self-assembly of lignin derivatives is described.